Urea derivatives represented by the general formula (C):

wherein R1 represents hydrogen, C1-6 alkyl or C3-8 cycloalkyl, and R2 represents hydrogen or methoxy, are known to exhibit excellent angiogenesis-inhibitory action (Patent document 1). Urea derivatives represented by general formula (C) also are known to exhibit powerful c-Kit kinase inhibitory action (Patent document 2, Non-patent document 1).
The preparing process described in Patent document 1 is useful as a process for preparing urea derivatives, but much room still remains for improvement in terms of total yield. It has therefore been desirable to develop an industrial process for preparing urea derivatives that gives a good total yield, as well as useful intermediates for such a preparing process.
Patent document 1 never discloses an efficient process for preparing urea compounds represented by the general formula (C), nor the useful intermediates represented by the general formulas (A-1) and (A-2), as according to the present invention.
Patent document 1: WO02/32872
Patent document 2: WO2004/080462
Non-patent document 1: 95th Annual Meeting Proceedings, AACR (American Association for Cancer Research), Volume 45, Page 1070-1071, 2004.